The present invention relates to electrical machines comprising coil windings which are fitted on component teeth with the aid of winding carriers. The present invention also relates to winding carriers for fitting a coil winding, in particular in the form of insulating laminations.
Electrical machines generally have electromagnetic components which are designed in the form of coil windings. The coil windings are each wound around one or more teeth of a stator or of a rotor in order to generate an excitation magnetic field. In the case of coil windings around an individual component tooth, turns of the coil winding are fitted in a spiral manner, wherein the turns are arranged in several layers. A preferred arrangement of the turns is the so-called orthocyclic winding. In the case of an orthocyclic winding, the wires of one layer of the coil winding lie, by at least 30% of their circumference, in the valleys between the individual turns of the layer which is situated therebeneath.
In order to ensure a sufficient degree of insulation between the component teeth and the coil winding, insulating laminations are often provided as winding carriers, said insulation laminations being arranged between the coil winding and the component tooth. Fitting of the coil windings onto the component teeth of the electrical machine can also be simplified by the winding carrier being wound before being placed on the component tooth, so that obstructions owing to the stator geometries can be avoided during winding.
In order to support the orthocyclic design of a winding during coil winding, the winding carriers are prestamped. The stamping structure of the stamping has a groove structure. The groove structure allows defined placement of the first layer of turns of the coil winding, the so-called root layer. The width of the grooves generally corresponds to the largest possible diameter of the winding wire used or is matched to said diameter.
The groove structure, which has been used to date, with a semicircular cross section can lead to winding errors in the layer structure since the individual turns within the groove structure can shift due to pressure from further winding layers which are arranged further above it, in particular when the width of the groove structure is greater than the actual diameter of the winding wire. This can occur since the width of the groove structure generally corresponds to the maximum diameter of the winding wire, the winding process and the associated curvature of the winding wire and the coiling onto the delivery rolls however leads to a change, in particular to a reduction, in the actual diameter of the winding wire. This may result in the winding wire resting in the groove structure of the winding carrier by way of only one support point, as a result of which shifting of the individual turns in the lateral direction (that is to say in the axial direction of the coil winding) cannot be prevented.
This can firstly lead to a disadvantage in the winding process. Secondly, subsequent calibration processes can lead to the turns of the wound layers being spread out. In a calibration process, after the coil winding has been wound, the fully wound coil winding is pressed together in order to compress the turns and push out the bulge of the winding wire on the longitudinal side of a rectangular coil. Support of the winding wire in the groove structure at only one support point also prevents uniform and adequate heat dissipation from the winding wire, via the winding carrier, to the component tooth of the electrical machine.